A battery-powered acoustic device intended to compensate for impaired hearing by transmitting amplified sound waves to the eardrum through air. It consists of a microphone or microphones and an amplifier in a case behind-the-ear (BTE) connected, via a wire, to a receiver (speaker) in the outer ear [receiver-in-the-ear (RITE)]. The microphone(s) receives sound waves and converts them into electrical signals which are increased by the amplifier and sent as sound waves, by the speaker, to the eardrum. The device is used for mild to profound hearing loss; most types are programmable to enable computerized adjustments for a patient's hearing loss and related factors.